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Researchers warn of serious risks from Australia carp control plans

Scientists have issued a warning to the Australian government about the potential ecological, environmental and economic repercussions of plans to manage invasive carp by releasing a deadly virus into rivers.

In an article published in the scientific journal Nature Ecology & Evolution, Dr Jackie Lighten and Prof Cock van Oosterhout from UEA's School of Environmental Sciences warn that the planned release of Koi Herpes Virus (KHV) into the Murray-Darling river system could pose a serious risk to global food security and threaten native species.

Carp are among the most invasive vertebrate species in the world and their highly competitive behaviour and ability to alter ecosystems can be detrimental to native species.

The Australian government made worldwide headlines last year with the news that up to A$15 million would be spent on a carp biocontrol program, in efforts to eradicate the freshwater pest and restore native ecosystems and fish populations.

Dr Lighten said: “The release of KHV to eradicate carp has been described as a safe, efficient, and manageable process. However the plans have been met with mixed feelings in both the academic and public communities within Australia and around the globe.”

Lighten and van Oosterhout outline four major concerns about the planned viral release:

Evolution of the virus to cause disease in endemic Australian species cannot be ruled out – therefore potentially threatening native species.

The large scale release of a notifiable virus poses a serious risk to global food security.

Millions of tons of rotting fish will have serious physiological impacts on other species and could lead to ecosystem crashes.

Carp have an extraordinary ability to bounce back after population crashes and because many individuals will be resistant to KHV (and won’t come in contact with all individuals) its ability to eradicate carp in the long run is small.

Prof van Oosterhout said: “KHV is a highly efficient killer of common carp, and since its initial outbreak and rapid global spread in the 1990s it has caused millions of dollars of losses to the carp aquaculture and angling industries. Carp is one of the most farmed fish in the world and an important source of protein in lower to middle income countries, so is vital to food security.

“KHV is on the World Organisation of Animal Health list of notifiable diseases, and although the virus has been detected in many different species from invertebrates to fish, so far disease symptoms have only been observed in carp. But we questions whether the release of a highly contagious virus into Australian waterways really be managed as simply as proposed.”

The method has been developed by the Australia’ national research body The Commonwealth Scientific and Industrial Research Organisation (CSIRO).

Prof Craig Primmer, fresh water ecologist and evolutionary biologist at University of Turku Finland who comes from Australia, said: “It is important for there to be a more open debate on the uncertainties, and potential negative consequences for this biological control approach, as it appears that most of the information the Australia public has received is via CSIRO PR, and once this is started, it may be difficult, if not impossible, to stop.”

Dr Lighten said: “We do not dispute the negative impacts which carp can have on ecosystems which they invade.

“Importantly however, the previous pre-emptive academic assessments of the feasibility for the planned KHV release in Australia have over-simplified crucial aspects surrounding efficiency and safety.”